package com.init.utils;

import com.google.gson.Gson;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import io.jsonwebtoken.gson.io.GsonSerializer;

import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;
import java.util.Date;
import java.util.UUID;

/**
 * JWT工具类
 * @author Atanycosts
 * @date 2024/4/9
 */
public class JwtUtil {

    //有效期为
    public static final Long JWT_TTL = 60 * 60 * 1000L * 12;// 60 * 60 * 1000 * 12  12小时
    //设置秘钥明文
    public static final String JWT_KEY = "AtanycostscodecodecodecodeAllbushpullcommit";

    public static String getUUID() {
        String token = UUID.randomUUID().toString().replaceAll("-", "");
        return token;
    }


    /**
     * 测试
     *
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        String token = "eyJhbGciOiJIUzI1NiJ9.eyJqdGkiOiJjM2IzMWZmM2EzYzM0MGU4OGNlYzA0NjBmZTQwMjI2ZCIsInN1YiI6IjE2MjM1MzA2NjgzNjI4MDUyNTAiLCJpc3MiOiJBdGFueWNvc3RzIiwiaWF0IjoxNjgzMjY0NDQ5LCJleHAiOjE2ODMyNjgwNDl9.JPcJ8vYWIJPuaXg16znJa0lBwrE3i3t_iDc5Icthxx4";
        Claims claims = parseJWT(token);
        System.out.println(claims);
    }

    /**
     * 生成Jwt
     *
     * @param subject token中要存放的数据（json格式）
     * @return
     */
    public static String createJWT(String subject) {
        JwtBuilder builder = getJwtBuilder(subject, null, getUUID());// 设置过期时间
        return builder.compact();
    }

    /**
     * 生成Jwt 重载
     *
     * @param subject   token中要存放的数据（json格式）
     * @param ttlMillis token超时时间
     * @return
     */
    public static String createJWT(String subject, Long ttlMillis) {
        JwtBuilder builder = getJwtBuilder(subject, ttlMillis, getUUID());// 设置过期时间
        return builder.compact();
    }

    /**
     * 生成Jwt,创建token  重载
     *
     * @param id
     * @param subject
     * @param ttlMillis
     * @return
     */
    public static String createJWT(String id, String subject, Long ttlMillis) {
        JwtBuilder builder = getJwtBuilder(subject, ttlMillis, id);// 设置过期时间
        return builder.compact();
    }

    /**
     * @param subject
     * @param ttlMillis
     * @param uuid
     * @return
     */
    private static JwtBuilder getJwtBuilder(String subject, Long ttlMillis, String uuid) {
        SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;
        SecretKey secretKey = generalKey();
        long nowMillis = System.currentTimeMillis();
        Date now = new Date(nowMillis);
        if (ttlMillis == null) {
            ttlMillis = JwtUtil.JWT_TTL;
        }
        long expMillis = nowMillis + ttlMillis;
        Date expDate = new Date(expMillis);
        return Jwts.builder()
                .setId(uuid)              //唯一的ID
                .setSubject(subject)   // 主题  可以是JSON数据
                .setIssuer("Atanycosts")     // 签发者
                .setIssuedAt(now)      // 签发时间
                .signWith(signatureAlgorithm, secretKey) //使用HS256对称加密算法签名, 第二个参数为秘钥
                .serializeToJsonWith(new GsonSerializer<>(new Gson())) // 添加序列化相关
                .setExpiration(expDate);
    }

    /**
     * 生成加密后的秘钥 secretKey
     *
     * @return
     */
    public static SecretKey generalKey() {
        byte[] encodedKey = Base64.getDecoder().decode(JwtUtil.JWT_KEY);
        SecretKey key = new SecretKeySpec(encodedKey, 0, encodedKey.length, "HmacSHA256");
        return key;
    }

    /**
     * 解析 , 解密
     *
     * @param jwt
     * @return
     * @throws Exception
     */
    public static Claims parseJWT(String jwt) throws Exception {
        SecretKey secretKey = generalKey();
        return Jwts.parser()
                .setSigningKey(secretKey)
                .parseClaimsJws(jwt)
                .getBody();
    }


}